This invention relates to time release fragrance sachets, methods of using same and methods of fabricating same. The sachets contain thermoplastic polymeric particles, including polymeric foam particles as control release compositions for use in the sachets.
An ever increasing requirement for air fresheners, including air fresheners for stored clothing exists for a slow controlled release device for slowly and controllably releasing fragrances into a gaseous environment in order to freshen air and in order to prevent stored clothing from becoming mildewed.
Slow release polymers containing perfumes are well known in the prior art. Thus, United Kingdom Patent Specification No. 1,589,201 assigned to Hercules, Inc. discloses a thermoplastic resin body consisting of a thermoplastic polymer of ethylene and 6-60 weight percent of a polar vinyl monomer selected from the group consisting of vinyl acetate, methyl acrylate, ethyl acrylate, butyl acrylate and acrylic acid wherein the perfumed resin body is suitable for the preparation of shaped objects from which perfume odor emanates over a prolonged period at a stable level
U.S. Pat. No. 3,505,432 discloses a method of scenting a polyolefin which comprises:
(a) mixing a first amount of liquid polyolefin, e.g., polyethylene or polypropylene with a relatively large amount of scent-imparting material to form a flowable mass; PA1 (b) forming drops from said mass and causing substantially instantaneous solidification of said drops into polyolefin pellets having a relatively large amount of scent-imparting material imprisoned therein; PA1 (c) melting said pellets with a second amount of said polyolefin, said second amount being larger than said first amount; and PA1 (d) solidifying the melt of (c). PA1 (i) extrusion of expandable beads; PA1 (ii) extrusion of thermoplastics containing a chemical blowing agent; and PA1 (iii) direct gas extrusion process. PA1 "the amount of blowing agent can vary widely depending on the resin and the type of product desired. However, generally about 7% blowing agent produces a product of about 5.6 lbs/cu. ft., while 18% blowing agent produces a product of about 1.9 lbs/cu. ft. . . . "
U.S. Pat. No. 4,247,498 issued on Jan. 27, 1981 discloses microporous polymers which are capable of containing volatile substances such as perfumes and the like in forms ranging from films to blocks in intricate shapes from synthetic thermoplastic polymers such as olefinic, condensation or oxidation polymers. In one embodiment of U.S. Pat. No. 4,247,498, the microporous polymers are characterized by relatively homogeneous three-dimensional cellular structure having cells connected by pores of smaller dimension. Also disclosed in U.S. Pat. No. 4,247,498 is a process for making microporous polymers from such thermoplastic polymers by heating a mixture of the polymer and compatible liquid (e.g., a perfume substance or the like) to form a homogeneous solution, cooling said solution under non-equilibrium thermodynamic conditions to initiate liquid-liquid phase separation and continuing said cooling until the mixture achieves substantial handling strength. Also disclosed in said U.S. Pat. No. 4,247,498 are microporous polymer products which contain relatively large amounts of such functionally useful fluids as perfume compositions and behave as solids.
U.S. Pat. No. 4,156,067 issued on May 22, 1979 discloses polyurethane polymers characterized by a molecular weight of above 6,000 and having lactone groups and hydroxyl groups in the polymer backbone being prepared by reacting a mixture of polyols, a polyfunctional lactone (e.g., epsilon caprolactone) and a polyfunctional isocyanate proportioned so as to provide certain desired polymer properties. It is indicated in said U.S. Pat. No. 4,156,067 that the product is soluble in alkaline solutions and may be used for light sensitive photographic layers on films, paper or glass; in drug delivery systems, as burn dressings; in body implants such as vascular prosthesis; in molding compositions; and in the manufacture of catheters as well as in delivery of perfume compositions in a slow release manner. It is further indicated in said U.S. Pat. No. 4,156,067 that the water absorptivity of the polyurethane/lactone polymers is above 10%, preferably in the range of about 20% to 60%, and these polymers may range in their physical properties from rigid solids to completely gel-like high water absorptive polymers. It is further indicated in said U.S. Pat. No. 4,156,067 that the polymers provide a leachable substrate wherein the leaching agent may be water, gases, alcohols, esters and body fluids, e.g., animal or human.
Extrusion of thermoplastic foams is well known in the prior art. Thus, the Modern Plastics Encyclopedia (published by the McGraw-Hill Publishing Company), 1982-1983 edition at pages 274 and 275 discloses a section authored by Fred Schrafft entitled "Extruding Thermoplastic Foams." Said article on pages 274 and 275 is incorporated by reference herein. It is indicated therein that three different processes are used for the extrusion of thermoplastic foams:
It is further indicated in the Schrafft article that the extrusion using a chemical blowing agent may be carried out on a normal single screw extruder, and the direct gas extrusion process may be carried out on single and twin screw extruders. It is further indicated in the Schrafft article that common blowing agents used in the process are hydrocarbons such as pentene or fluorocarbons such as 11, 12 and 114. It is further stated that: